Kozo Hanayama

Functional status and muscle strength in people with Duchenne muscular dystrophy living in the community.

OBJECTIVEnTo describe activity limitation of people with Duchenne muscular dystrophy who are living in the community and to correlate it with age and muscle strength.nnnDESIGNnDescriptive, correlational.nnnSUBJECTSnTwenty-seven children with Duchenne muscular dystrophy aged 7-14 years who are living in the community.nnnMETHODSnThe subjects activity limitation was evaluated using the Functional Independence Measure and the muscle strength of their major upper and lower limb muscles was evaluated with manual muscle testing. The Functional Independence Measure was correlated with age and manual muscle testing, and the pattern of activities of daily living limitations and factors related to it were analysed.nnnRESULTSnThere were significant correlations between age and averaged MMT score (Spearmans rho = -0.63, p < 0.01), age and Functional Independence Measure motor score (rho = -0.52, p < 0.01), and Functional Independence Measure motor score and averaged manual muscle testing (rho = 0.77, p < 0.01). At similar manual muscle testing level, children with good cognitive function (Functional Independence Measure cognitive score > or = 26) showed significantly higher Functional Independence Measure motor scores than those with poor cognitive function (Mann-Whitney U test, p < 0.01). For individual Functional Independence Measure items, eating and bowel management were the easier, whereas transfer and stair climbing were the more difficult. Patients with mean muscle strength > or = grade 3 were rated as relatively independent, while those with a mean muscle strength < grade 3 were rated as maximal or total assistance (Mann-Whitney U test, p < 0.05).nnnCONCLUSIONnActivities of daily living in patients with Duchenne muscular dystrophy are related to age and muscle strength, and manual muscle testing grade 3 is an important cut-off point to predict their disability.

Premotor potential study in carpal tunnel syndrome

Introduction: Premotor potentials (PMPs) precede compound muscle action potentials evoked from the second lumbrical muscle after median nerve stimulation. Although PMP has been identified as a median sensory nerve action potential, few reports have documented the significance of PMP parameters for diagnosing carpal tunnel syndrome (CTS). Methods: We investigated the relationships between PMP parameters and results of 6 standard median nerve conduction studies in 74 CTS hands. Results: Significant correlations were noted in all comparisons. PMP conduction velocity was strongly correlated with the sensory conduction velocity between wrist and digit 2 (r2 = 0.91). Moreover, PMP parameters were significantly correlated with neurophysiological severity of CTS. Conclusion: Measuring PMP parameters with a second lumbrical–interosseous study may be useful for diagnosing CTS. Muscle Nerve, 2012

Dysphagia in patients with duchenne muscular dystrophy evaluated with a questionnaire and videofluorography

Purpose. To investigate swallowing problems in patients with Duchenne muscular dystrophy (DMD) using a questionnaire and videofluorography (VF). Method. A questionnaire survey was performed of swallowing-related symptoms and VF in 31 male patients with DMD (mean age 19.9 years, range 9 – 26 years). The relationships among age, frequency of symptoms and VF abnormalities were analysed using Spearmans rank correlation. The differences in VF abnormalities among different food textures were analysed with the Kruskal – Wallis test. Results. Symptoms related to pharyngeal phase dysfunction were more frequent than those related to oral and oesophageal phases. Coughing while eating was seen in 71% of the patients, choking while eating in 32% and the need to clear the throat in 26%. VF abnormalities were observed in 30 patients (96.8%). Common VF abnormalities included pooling in the valleculae (90.3%) and in the pyriform sinus (90.3%). Pharyngo-oral regurgitation was seen in 35.5% of the patients. Pooling in the pyriform sinus after repeated swallowing seen in VF correlated significantly with symptoms related to the pharyngeal phase (Spearmans rho 0.356 – 0.544). Conclusion. Because oropharyngeal dysphagia in DMD was evident in teenage patients as well as those without clinical symptoms, VF is recommended in patients with DMD.

The origin of the premotor potential recorded from the second lumbrical muscle in normal man

OBJECTIVEnWhen recording with a palm electrode, a premotor potential precedes the compound muscle action potential (CMAP), evoked from the second lumbrical (2L) muscle following median nerve stimulation. The purpose of this study was to determine the origin of the premotor potential from the 2L.nnnMETHODSnWe recorded potentials with multi-channel electrodes in the palm and finger in a bipolar or referential manner, stimulating the second digit or median nerve at the wrist.nnnRESULTSnWe recorded the traveling nearfield sensory nerve action potential (SNAP) and stationary negative potential in the palm. The peak latency of the stationary negative potential was the same as the one of the near-field potential of the digital sensory fibers at the base of the second finger. The onset of the premotor potential from the 2L muscle is aligned to the palmar SNAP in a bipolar manner by antidromic stimulation.nnnCONCLUSIONSnWe conclude that the premotor potential from the 2L muscle is composed of a SNAP arising from antidromically activated palm sensory branches and a far-field potential generated by the median digital nerve fibers as they pass from the palm into the second finger.nnnSIGNIFICANCEnOur results might be useful for evaluating the 2L-interossei test for diagnosing carpal tunnel syndrome.

31. Modified second lumbrical-interossei method

This study was aimed to assess a correlation of event-related desynchronization (ERD) with primary motor cortex (M1) excitability during hand motor imagery. M1 excitability was tested by motor evoked potentials (MEPs), intracortical inhibition (ICI) and intracortical facilitation (ICF), using transcranial magnetic stimulation (TMS). Twenty healthy subjects were recruited in this study. Each subject performed 30 trials comprising 7 s of rest followed by 5 s of motor imagery of either right wrist flexion or extension. Subjects received real-time visual feedback of the ERD magnitude of electroencephalogram signals recorded over the hand area of the left M1. TMS was applied to the left M1 when ERD exceeded 5% or 15% thresholds during motor imagery. MEP size, ICI and ICF were recorded from the agonist muscle of the motor imagery. During hand motor imagery with ERD, MEP sizes increased and ICI reduced (p < 0.05), but there was no significant change in ICF. The changes of MEP-size and ICI were correlated with ERD magnitude. Our findings suggest that ERD magnitude may indicate changes of M1 excitability.

60. Changes in motor cortical excitability following electrical stimulation of the common peroneal nerve

acute sensory ataxia. The positive anti-Hu antibody suggested that he had anti-Hu-associated paraneoplastic subacute sensory neuropathy. The conventional nerve conduction studies and somatosensory evoked potentials revealed severe sensory neuropathy. For magnetic cerebellar stimulation, the test magnetic stimulus over the left primary motor cortex (M1) was preceded by the conditioning stimulus over the right cerebellum. Motor evoked potential was recorded from the right first dorsal interosseous muscle. The suppressive effect of magnetic cerebellar stimulation on the contralateral M1 was abnormally reduced. The results indicated that cerebellar efferent pathway or dentatothalamocortical pathway was involved in this patient, although cerebellar signs could not be evaluated due to severe sensory neuropathy. Magnetic cerebellar stimulation might be useful to reveal cerebellar dysfunction masked by coexisting sensory ataxia in patients with paraneoplastic sensory neuropathy.

P30-2 The origin of the premotor potential recorded from the second lumbrical (2): investigation in patient with carpal tunnel syndrome

Purpose: Recently, a premotor potential (PMP) recording from a second lumbrical muscle (2L) has been identified as a median sensory nerve action potential (SNAP), but the origin of that has remained uncertain. The purpose of this study was to investigate the latency of PMP-2L and the correlation with the latency of digital SNAP in patients with carpal tunnel syndrome (CTS). Methods: In 36 CTS hands, the PMP-2L was recorded with the palm active electrode following median nerve stimulation at the wrist. The median SNAPs activating antidromically from 1st, 2nd and 4th digits were also recorded, and the latencies of those were verified the correlations with the latency of PMP-2L. Results: PMP-2L could be recorded in 28 patients but no evoked in 8 patients. In severe affected CTS patients that the median SNAPs did not recorded in each digit, it was difficult to record with the PMP-2L either. The significant correlations with the latencies of all three digital SNAPs were observed. The correlation (R-square) with the SNAP recorded from 1st, 2nd and 4th digit was 0.65, 0.91 and 0.38 respectively. Conclusions: We considered that the origin of the PMP-2L is a nearfield SNAP arising from antidromically activated median 2nd digit sensory branch.

P30-1 The origin of the premotor potential recorded from the second lumbrical (1): in normal subject

Objective: To investigate the involvement of primary motor cortex (M1) while observing handwritten known or unknown letters using motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS). Methods: 11 right-handed healthy volunteers with written informed consents were involved. Hand written and block letter images of 30 characters were prepared as stimuli; 10 alphabets, 10 hiragana, and 10 kanji of daily use in Japan (Experiment 1). Arabic letters were used as a control condition of unknown letters (Experiment 2). Subjects look at a screen, where letter stimuli appear in a random order. MEPs were recorded from right FDI muscle, TMSs were given at the timing 100, 200, 300, 400 or 500 ms following each stimulus onset. Results: For handwritten condition, MEPs were significantly small at 300 and 400 ms in comparison to block-letter condition. The result was dependent on the subjects’ knowledge of letters. Conclusion: This result suggests the involvement of M1 hand area in the neural network associated with letter recognition.

114. A case of polyneuropathy with hypertrophic spinal radiculopathy mimicking neurofibromatosis

This report illustrate a case of polyneuropathy masquerading as neurofibromatosis due to multifocal enlargements of spinal nerve roots. The patient complained of numbness and pain of the hands and leg weakness from six years later at age 67, but could gait with cane independently and draw picture with intention tremor. Magnetic resonance imaging (MRI) T2 weighted image through cervical spine demonstrated C6-7 spinal cord compression bilaterally by cervical root tumors like neurofibromatosis and enlargements of spinal nerve roots and brachial, lumbosacral plexus of nerves. Nerve conduction studies were almost no evoked response but median nerve which demonstrated prolonged distal latency and reduced compound muscle action potential with temporal dispersion, suggesting a diagnosis of demyelinating neuropathy. Somatosensory evoked potential of the median nerve revealed prolonged latency, and motor evoked potentials obtained from abductor pollicis brevis, and abductor digiti minimi by transcranial magnetic stimulation have prolonged latency and temporal dispersion. Sural nerve biopsies showed segmental demyelination, remyelination, lymphocyte infiltration and onion-bulb formation, suggesting chronic inflammatory demyelinating polyneuropathy. The patient did not have family history and reject furthermore genetic study, we could not deny the possibility of hereditary hypertrophic neuropathy like Charcot– Marie–Tooth disease.